<!DOCTYPE html>
<html>

<head>
    <meta charset="UTF-8" />
    <title>11-执行上下文环境的理解</title>
</head>

<body>
    <script>
        var a = 10;
        var b = 20
        function fn(a, b) {
            a = 30;
            b = 40
            console.log(a, b)
        }
        fn(a, b)
        console.log(a, b)  // 10 20
    </script>
</body>

</html>